目的　研究缺血低氧性脑损伤对新生大鼠远期学习记忆和海马CAl区神经元超微结构的影响 ,并探讨其作用机理。方法　 7日龄Wistar大鼠 36只随机分为实验组和正常对照组 ,随机取 2 1只行右侧颈总动脉结扎后吸入 8%氧气 2h建立HIE模型。至 80d左右行Y迷宫测试学习和记忆能力 ,然后用透射电镜观察海马CAI区锥体神经元的超微结构变化。结果　HIE组大鼠学习和记忆能力均明显低于正常对照组 (P <0 0 1,P <0 0 5 ) ;其CAI区锥体神经元见部分核膜消失、线粒体嵴模糊、数量明显减少等超微结构改变。结论　新生期缺血低氧性脑损伤可致大鼠远期学习和记忆障碍 ,可能与缺血低氧后海马结构中神经元改变导致突触连接和信息传递障碍有关 Objective To investigate the effect of ischemic hypoxic-ischemic brain damage on long-term learning and memory and neuronal ultrastructure of hippocampal CA1 region in neonatal rats and its mechanism of action. Methods Thirty-six Wistar rats, 7 days old, were randomly divided into experimental group and normal control group. HIE model was established by inhalation of 8% oxygen after 21 ligation of right common carotid artery in 21 rats. To about 80d Y maze test learning and memory ability, and then observe the ultrastructure of pyramidal neurons in hippocampal CAI area by transmission electron microscopy. Results The learning and memory abilities of rats in HIE group were significantly lower than those in normal control group (P <0.01, P <0.05). The pyramidal neurons in CA1 area disappeared and some mitochondrial cristae were diminished Other ultrastructural changes. Conclusion Neonatal hypoxic-ischemic brain damage can cause long-term learning and memory impairment in rats, which may be related to neuronal changes in the hippocampal formation resulting in synaptic connections and information transfer disorders following ischemia and hypoxia